Drum series printer with type members arrested by staggered stop pawls

ABSTRACT

A plurality of type carriers having spaced type characters and stop teeth thereon are yieldably driven past a printing station and are arrested by engagement of electromagnetically controlled stop pawls with selected ones of the stop teeth. The type characters and stop teeth on certain of the type carriers are staggered relative to the type characters and stop teeth on other type carriers to reduce the mechanical &#39;&#39;&#39;&#39;break-away&#39;&#39;&#39;&#39; load and the electrical load.

United States Patent 1191 Clary Nov. 4, 1975 1 DRUM SERIES PRINTER WITH TYPE MEMBERS ARRESTED BY STAGGERED STOP PAWLS [75] Inventor: John G. Clary, Pasadena, Calif.

[73] Assignee: Addmaster Corporation, San

Gabriel, Calif.

[22] Filed: Mar. 13, 1974 [21] Appl. No.: 450,846

521 u.s.c1. ..101/93.37;101/9322;101/99 511 1m. 01. ..B41J l/08 58 Field of Search 101/95, 99, 110, 93.18,

[56] References Cited UNITED STATES PATENTS 5/1933 Peirce 101/93.22 X 3/1967 Hickerson 101/110 X 3.517.611 6/1970 Fink 101/93.31

3.664259 5/1972 Weinkle 101/95 X 3,732,812 5/1973 Bremner 101/99 3,756,147 9/1973 Gross et a1 101/95 Primary Examiner-Edgar S. Burr Assistant Examiner-Edward M. Coven Attorney, Agent, or Firm-Fred N. Schwend ABS I'RACT A plurality of type carriers having spaced type characters and stop teeth thereon are yieldably driven past a printing station and are arrested by engagement of electromagnetically controlled stop pawls with selected ones of the stop teeth. The type characters and stop teeth on certain of the type carriers are staggered relative to the type characters and stop teeth on other type carriers to reduce the mechanical break-away load and the electrical load.

7 Claims, 6 Drawing Figures Sheet 1 of 2 3,916,786

US. Patent Nov. 4, 1975 US. Patent Nov. 4, 1975 I Sheet20f2 3,916,786

DRUM SERIES PRINTER WITH TYPE MEMBERS ARRESTED BY STAGGERED STOP PAWLS BACKGROUND OF THE INVENTION rested at different times to position selected type characters to be printed.

2. Description of the Prior Art Printers of the above type generally comprise yieldably operated devices for advancing the type members until they are arrested by settable stop pins or pawls. In cases where the type members are driven through extensible springs, the springs at certain times, depending on the positions in which the type members are atrested, must be stretched a maximum amount. Since printers of this type may incorporate as many as 16 denominationally arranged type membersQand since the springs must operate properly when in their most collapsed conditions, the aggregate load applied to all actuator springs when stretched .to their maximum amount may require an abnormally large power drive unit.

In order to reduce the power required, detent drive mechanisms, such as that disclosed and claimed in the B. F. Kuhne U.S. Pat. No. 3,094,278 have been developed. Such drive mechanisms have proved superior since the break-away force or that force necessary to uncouple a type member or other driven element from the drive means is the same regardless of when the break-away occurs.

Although such detent drive type actuators are highly satisfactory in reducing the amount of power required to drive the various type members or the like, there are certain times, i.e. when all type members are arrested at the same time to locate the same type elements at the printing station, that an abnormal instantaneous or peak load occurs which often becomes the determining factor as to the size of the power drive unit. Although a relatively weak drive motor can be used under most conditions where the break-away occurs at different 'times in the different denominational orders, when such break-away occurs simultaneously in all or most orders, it may momentarily slow down the drive motor and could possibly stall the same.

Further, in cases where electromagnetically operated stop pawls are employed to arrest the type members or atively feeble control currents are encountered.

SUMMARY OF THE INVENTION A principal object 'of the present invention is to reduce abnormal or peak mechanical and/or electrical loads encountered in differentially driving type members or the like in printers of the above type.

Another object is to enable relatively small drive motors to be employed for printers of the above type.

According to the present invention, denominationally arranged type members, each carrying a set or font of type characters, are advanced past the printing station by a common drive member through yieldable connections, such as of the spring detent type, and are arrested by electr'omagnetically operated pawls.

Certain of the type members are staggered relative to others so that even when the same characters are to be printed in all or a large number of denominational orders, the stop pawls in certain orders may be actuated at different times and therefore the instantaneous or peak electrical load required to actuate all pawls is significantly reduced, thereby requiring a smaller electrical power unit. Further, since the break-away" point is different for certain of the type members, the instantaneous mechanical load occasioned by the arresting of a number of the type members at the same type character positions will also be reduced considerably and therefore a much weaker and less expensive drive motor need be used.

BRIEF DESCRIPTION OF THE DRAWINGS The manner in which the above and other objects of the invention are accomplished will be readily understood.on reference to the following specification when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a sectional elevation view of a data printer embodying a preferred form of the present invention.

FIG. 2 is a sectional view illustrating the drive mechanism for the printer.

FIG. 3 is an enlarged fragmentary view illustrating the staggered relation of certain of the printing sectors and is taken along line 3-3 of FIG. 4.

FIG. 4 is a transverse sectional view through part of the printer and is taken substantially along the line DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the printer disclosed therein comprises a plurality of plastic printing sectors 11 arranged in side-by-side relation. The sectors 11 are pivotally mounted independently of each other on a rockable support shaft 12 rotatably supported in bearings 13, FIG. 4, carried by spaced printer side frames, one of which is shown at 14. Such side frames are suitably secured to a base frame 15.

Each sector 11 has a somewhat flexible arcuate type section 16 which is integrally connected to the main body of the sector 11 by end portions 17 and 18 of greater flexibility than that of the main part of the section 16. Printing type characters 20 ranging in value from a zero type character 20' are spaced along the length of the type section 16.

Means are provided to yieldably advance the various type sectors 11 clockwise from their illustrated initial or home positions until differentially arrested in positions presenting selected type characters 20' or 20 at a printing station 21. After a printing impression, as will be described later, the sectors are returned counterclockwise to their home positions. For the, purpose of moving the sectors 11, a cyclically operable drive shaft 22, FIG. 2, is provided which is suitably driven clockwise one revolution for each cycle of the printer. An arm 23 carriedby shaft 22 is pivotally connected at:24 to a link 25 which, in turn, is pivotally connected at.26 to an arm-27 attached to the shaft 12.

Cam'arms, one of which is shown at 28, are fastened to the shaft 12 and carry the opposite endsofa bail rod 30 which extends through openings 31 in the sectors 1 l and frictionall-y'engages depressions 32formed in yieldable tails 33 formed integral with the-sectors 11. The bail rod 30 also rests against shoulders 34 formed on the sectors 11. As the drive shaft 22 and arm 23 move clockwise through the first half of a revolution, link 25 and arm 27 rock the shaft 12 and thus carry the bail rod 30 through approximately 90 to yieldably drive the various sectors 11- correspondingly.

Means are provided to selectively arrest the different type sectors 1 1 so as to present selected type characters 20 at the printing station 21. For this purpose, a stop pawl 35 is provided for each sector 11. The pawls 35 are independentlypivoted on a rod 36 and are adopted to engage any of a plurality of spaced stop teeth 37 foundon the sectors 11. Each stop pawl 35 is frictionally held in either its illustrated retracted position min a blocking position in engagement with one of the teeth 37 of its associated sector 11 by means of a spring tail 38 which is formed integral therewith and frictionally engages the rod 36. i

The stop pawls 35 are moved into blocking relation with the sectors 11 by electromagnetic coils 40. For

' this purpose, each coil 40 surrounds one leg of a U- shaped magnet core 41, FIG. 1, and is mounted within a plastic housing 42. Upon energization of a coil 40, an armature 43 pivoted at 44 is attracted upwardly and in so doing forces a rod 45 upwardly to rock the associated pawl 35 into blocking relation with whichever sector tooth 37 is next adjacent the pawl at the time of its energization. i

A paper tape 46 is guided endwise through a guide channel 47 between a stationary platen 50 and an ink ribbon 51 (see also FIG. 3), and is deflected upwardly by a concave guide surface formed on a tear-off mem-- ber 49.

Suitable line spacing means (not shown) is provided to push the paper 46 endwise through the channel 47 and past the platen 50 following each printing operation.

A combined aligning and printing bar 151 (see also FIG. 2) extends through openings 31 in the sectors 11 and is guided for vertical movement, toward and away from the platen 50, in guide slots 52 formed in the printer side frames, i.e. 14.

Cam formations 53 are formed on the cam levers, i.e. 28, and are arranged toengage the rod 151 after the and platen 50.so as to transfer an imprint of such type charactersonto the paper tape.

After the printing operation, the bail rod 30 is returned counterclockwise, engaging the sector shoulders 34 to likewise return the sectors to their illustrated home positions. Duringthis time, the teeth 37 cam the stop pawls 35 .to their illustrated retracted positions where they are retained by their friction tails 38.

In accordance with the presentinvention, the type characters andstop teeth of certain of the sectors are initially angularly offset or staggered relative to the i type characters and stop teeth of the remaining sectors by an amount equal to one half the distance between two adjacent stop teeth. This is shown in FIG. 3 whereir two adjacent sectors 1 la and 1 lb are depicted, both being in their initial positions with their shoulders 34 in engagement with the vbail rod 30. It will be noted that, although the pawls 35 are in alignment with each teeth. Also, therefore, the type characters 20a of sector 11a" are similarly located midway between adjacent type characters 20b of sector 11b. Timing means is provided to properly time transmis sion of data signals from a'data source (not shown) and for controllingenergization of the coils 40. For this purpose, a light shutter 54 (FIGS. 2, 4 and 5) having a series of openings 55 therein is attached by screws 56 to a cam lever'28. The screws 56 pass through arcuate slots 57 in a'shut't'er 54, permitting angular adjustment of the same; During a cycle of the machine, the shutter 54 passes between a lamp 60 and a photodiode 61. The lamp 60 and photodiode 61 are mounted in a housing 62 supported by the base frame 15, the lamp being effective to project a narrow beam of light across the path of the shutter and onto the photodiode.

Describing now the electronic control circuitry for the coils 40, each coil is connected at one end to a source 611 of positive potential and at its opposite end,

through a'drive circuit 621 to a signal line 63, over which timed positive going signal pulses are applied.

Each drive circuit 621 comprises a Darlington arrangement of two NPN transistors 65 and 66 as shown in FIG. 6. A positive going signal applied to the base of transistor 65 will turn the-latter on which, in turn, will turn on the transsitor66 and therefore complete a circuit through the respective coil 40 to ground.

- The photodiode 61 is connected in circuit with a resistor 67 between a source 68 of positive potential and ground.

The diode 61 is also connected to the base of an NPN transistor 70 which is connected between ground and aseries of diodes 71 connected to alternate ones 63b of the signalllines 63. The collector of transistor 70 is connected to asource 72 of positive potential and to the base of. a second. NPN transistor 73. The latter is connected between ground and a series of diodes 74 connected to intermediate ones 63a of the signal lines lines 63b to low level potentials, preventing data signals from being transmitted through the associated drive circuits 63b to the alternate coils 40b associated with the sectors 11!). At this time, diodes 74 have no effect on the intermediate signal lines 634 and, therefore, zero timed data signals can be applied to control one or more of the alternate coils 40a associated with sectors 11a to move the associatedpawls 35 into the path of the first sector tooth or teeth 37a of the associated secor or sectors 11a and thus arrest such type sector or type sectors in position to print a zero character.

Timing of the data signals applied to the lines 63 is preferably also controlled by the shutter 54 and for this purpose timing signals are applied over line 79 to the data source (now shown). i

It should be noted that each data signalextends over a time period sufficient for the pawls 35 to be moved to block the appropriate teeth 37a and 37b of the corresponding sectors, as will appear presently.

When the shutter 5 4 has movedplockwise an amount substantially equal'to one half the pitch between two adjacent sector teeth 37, itwill cut off photodiode 61, thereby turning diode 70 off and diode 73 onQTherefore, diodes 7l will unclamp the respective alternate signal lines 63b to enable energizing of the alternate coils 40b and diodes 74 will clamp the intermediate signal lines 63a to prevent energization of the alternate coils 40a. Accordingly, if data signals are applied at this time over any of the signal lines 63b, the corresponding sectors 11b will be arrested to position their zero type characters a at the printing station.

Accordingly, it will be seen that even if all zero characters were to be printed in a line across the printer, only one half of the type sectors 11 will be arrested at one point in time, the other halfbeing arrested one half increment later. Thus, the break-out load incurred by arresting the sectors 11 by their stop pawls 35 will be reduced by one half, enabling the use of a much smaller drive motor. On the other hand, in such case, since only half of the coils 40 would be energized at one point in time, a much smaller power supply for energizing such coils is necessary.

Since the staggered relation of the type characters and stop teeth of the sectors applies for all type characters, the same reduced mechanical and electrical loads will be obtained for any other values wherein a large number of similar characters are to be printed in the same print line.

The various type sectors 11 have been disclosed as alternately staggered, as shown particularly in FIG. 4. However, they may also be arranged in other groupings. For example, the left hand group of sectors may be formed as depicted by sector 11a and the right hand group of sectors may be formed as depicted by sector means for actuating said stop pawls at different times printing impression means for transferring an imprint on said type characters at said printing station to a record medium,

the type characters and stop teeth of a first series of said type devices being spaced at a single distance from said printing station and from their respective stop pawls, and

the type characters and stop teeth of a second series of said type devices being spaced at a single different distance from said printing station and from their respective stop pawls when all said type devices are in said initial positions.

2. A data printer comprising i a pluraliity of type members having spaced type characters thereon,

, said type members having stop teeth thereon spaced the same as said type characters,

yieldable drive'means for advancing said type members from initial positions past a printing station, stop pawl devices engageable with said teeth of respective ones of said type members,

means for actuating said stop pawls at different times to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, and printing impression means for transferring an imprint from said type characters at said printing station to a record medium,

the stop teethof a first series of said type members being spaced a single distance from their respective stop pawls, and

the teeth of a second series of said type members being spaced asingle different distance from their respective stop pawls when said type members are in said initial positions.

3. A data printer as defined in claim 2 wherein the difference in spacing between a stop tooth on a type member of said first series and a corresponding stop tooth on a type member of said second series is less than the spacing between adjacent stop teeth on a type member of said first series.

4. A data printer as defined in claim 3 wherein said difference in spacing is one-half the spacing between said adjacent stop teeth on said type member of said first series.

5. A data printer comprising a plurality of type devices having spaced type characters thereon,

each of said type devices having stop teeth thereon spaced to correspond with the spacing of said type characters;

yieldable drive means for advancing said devices from initial positions past a printing station,

stop pawl devices engageable with said teeth of respective ones of said type devices,

means for actuating said stop pawls at different time periods to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, and

printing impression means for transferring an imprint from said type characters at said printing station to a record medium,

the stop teeth of a first series of said devices being spaced at a single distance from their respective stop pawls, and the stop teeth of a second series of said devices being spaced at a single different dis 7 respective stop pawl and the passage of a tooth of said second series past its re'spective stop pawl.

7. A data printer comprising a plurality of type members having spaced type charactersthereon, i I said type members having stop teeth thereon spaced the same as said type characters,

yieldable drive means for advancing said members M from initial positions pasta printing station, stop pawl devices engageable withsaid teeth of respective'ones of said type members,

means for actuating said stop pawls at difi'erent' time 7 periods to engage different ones of said teeth whereby to present different ones of said type charv acters to said printing station, printing impression means for transferring an imprint from said type characters at said printing station to a record medium, the stop teeth of a first series of said type members being spaced apart the same distances as stop teeth 7 of a second series of said .type members and being v staggered relative to said stop teeth of said second seriesvby anamount equal tonne-half the spacing a between'adjacent teeth of one of said type when said type members are in said initial positions, and k 1 actuating means actuating said stop pawls of said second series later than actuation ofsaid stop pawls said first series by amounts corresponding to one-half thedifference between passage of adjai cent teeth of a said type member past its respective. 2 a a i stop pawl.

ef'ee :1: 

1. A data printer comprising a plurality of type devices having spaced type characters thereon, each of said type devices having stop teeth thereon spaced to correspond with the spacing of said type characters; yieldable drive means for advancing said devices from initial positions past a printing station, stop pawl devices engageable with said teeth of respective ones of said type devices, means for actuating said stop pawls at different times to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, and printing impression means for transferring an imprint on said type characters at said printing station to a record medium, the type characters and stop teeth of a first series of said type devices being spaced at a single distance from said printing station and from their respective stop pawls, and the type characters and stop teeth of a second series of said type devices being spaced at a single different distance from said printing station and from their respective stop pawls when all said type devices are in said initial positions.
 2. A data printer comprising a pluraliity of type members having spaced type characters thereon, said type members having stop teeth thereon spaced the same as said type characters, yieldable drive means for advancing said type members from initial positions past a printing station, stop pawl devices engageable with said teeth of respective ones of said type members, means for actuating said stop pawls at different times to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, and printing impression means for transferring an imprint from said type characters at said printing station to a record medium, the stop teeth of a first series of said type members being spaced a single distance from their respective stop pawls, and the teeth of a second series of said type members being spaced a single different distance from their respective stop pawls when said type members are in said initial positions.
 3. A data printer as defined in claim 2 wherein the difference in spacing between a stop tooth on a type member of said first series and a corresponding stop tooth on a type member of said second series is less than the spacing between adjacent stop teeth on a type member of said first series.
 4. A data printer as defined in claim 3 wherein said difference in spacing is one-half the spacing between said adjacent stop teeth on said type member of said first series.
 5. A data printEr comprising a plurality of type devices having spaced type characters thereon, each of said type devices having stop teeth thereon spaced to correspond with the spacing of said type characters; yieldable drive means for advancing said devices from initial positions past a printing station, stop pawl devices engageable with said teeth of respective ones of said type devices, means for actuating said stop pawls at different time periods to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, and printing impression means for transferring an imprint from said type characters at said printing station to a record medium, the stop teeth of a first series of said devices being spaced at a single distance from their respective stop pawls, and the stop teeth of a second series of said devices being spaced at a single different distance from their respective stop pawls when said type members are in said initial positions, said actuating means actuating said stop pawls for said first series and said second series at different times within any one of said time periods.
 6. A data printer as defined in claim 5 wherein said actuation of said stop pawls for said second series is delayed by an amount corresponding to the difference between the passage of a tooth of said first series past its respective stop pawl and the passage of a tooth of said second series past its respective stop pawl.
 7. A data printer comprising a plurality of type members having spaced type characters thereon, said type members having stop teeth thereon spaced the same as said type characters, yieldable drive means for advancing said members from initial positions past a printing station, stop pawl devices engageable with said teeth of respective ones of said type members, means for actuating said stop pawls at different time periods to engage different ones of said teeth whereby to present different ones of said type characters to said printing station, printing impression means for transferring an imprint from said type characters at said printing station to a record medium, the stop teeth of a first series of said type members being spaced apart the same distances as stop teeth of a second series of said type members and being staggered relative to said stop teeth of said second series by an amount equal to one-half the spacing between adjacent stop teeth of one of said type members when said type members are in said initial positions, and said actuating means actuating said stop pawls of said second series later than actuation of said stop pawls of said first series by amounts corresponding to one-half the difference between passage of adjacent teeth of a said type member past its respective stop pawl. 